NK cells can work with mediators to help fight cancer

Natural killer (NK) cells are being combined with three different immune mediators to investigate how the human body's own defences can fight off cancer.

The cells are perceived by many experts to be effective weapons to treat the disease and exist as part of the innate immune system, meaning they can respond to a variety of different cancers.

As well as this, they kill tumour cells that have lost a specific target and travel through the body unnoticed by other immune cells.

Dr Adelheid Cerwenka, together with her team at the German Cancer Research Centre, is attempting to enhance the potential of NK cells in mice by using interleukins 12, 15 and 18.

These were activated in a culture dish before being injected into cancerous mice, which led to tumour growth slowing down significantly.

The animals survived significantly longer and, in one quarter of them, the tumours regressed entirely. However, without prior treatment, the NK cells were found to be ineffectual.

Researchers noted that the cells appear to be re-stimulated by other immune cells in the bodies of mice, meaning they were kept in an active state.  After a period of three months, immunologists discovered functional NK cells in mice, even after the tumours had been rejected.

Nonetheless, the NK cells were only able to shrink tumours if prior radiation treatment had taken place.

"The big problem in using NK cells for therapy is their rapid loss of activity, hence their aggressiveness. Although there are good treatment results for certain types of blood cancer, NK cells have been clinically effective in fighting solid tumors only in a few cases.

"We previously thought immunological memory exists only in cells of the adaptive immune system," Ms Cerwenka explained.

The results come after Cancer Research UK found that more than 33,000 childhood cancer survivors will be living in the UK by the end of 2012.

This indicates the progress made in treatments for the disease, with survival statistics rising from three in ten in the 1960s to eight in ten in modern society.

Posted by Ben Evans